The disclosure relates to systems and methods of switching an electrical load (for example, a lighting load) between primary and backup power sources.
Power distribution systems for critical electrical devices (such as emergency lighting) often include a primary power source and a backup power source. These power distribution systems include automatic transfer switches which automatically switch the electrical devices to the backup power source when the primary power source fails. General-purpose automatic transfer switches that are designed to comply with electrical safety standards (such as those typically used for feeder circuits) are large and expensive. Smaller conventional automatic transfer switches (such as those used for branch circuits) often do not comply with current electrical safety standards such as National Fire Protection Association (NFPA) 70, Underwriters Laboratories (UL) 1008, and the like.